Dwarf planet discovery hints at a hidden Super Earth in solar system.

The orbits of Sedna (orange) and dwarf planet 2012 VP113 (red). Also shown are the orbits of the giant planets (purple). The Kuiper belt is the dotted light blue region. Illustration: Scott S Sheppard/Carnegie Institution for Science

Astronomers have increased the size of the observable solar system after spotting a 450-km wide object orbiting the sun.

The lump of ice and rock circles the sun at a greater distance than any known object, and never gets closer than 12bn kilometres – 80 times the distance from Earth to the sun.

If its size is confirmed it could qualify as a dwarf planet in the same category as Pluto. Researchers said the discovery proves the existence of the inner Oort cloud, a region of icy bodies that lies far beyond the orbit of Neptune – which at 4.5bn kilometres from the sun is the most remote planet in the solar system.

Until a proper name is decided upon, the body is known only as 2012 VP113. According to the science journal Nature, the team that discovered it call it VP for short, or “Biden”, after US vice president Joe Biden.

Its pink tinge comes from radiation damage that alters the make-up of frozen water, methane and carbon dioxide on the surface.

Though exciting in its own right, the discovery raises a more tantalising prospect for many astronomers: that a “Super Earth” up to 10 times the mass of our planet orbits the sun at such a great distance that it has never been seen.

Three images of the newly discovered dwarf planet 2012 VP113 taken about two hours apart on 5 November 2012. Photograph: Scott S Sheppard/Carnegie Institution for Science

Astronomers found 2012 VP113 by taking snapshots of the night sky an hour or so apart with an instrument called the Dark Energy Camera on the US National Optical Astronomy Observatory telescope in Chile. When they turned the images into a time-lapse movie of the sky, they could see the new body moving against the background of stationary stars.

“This object has the most distant orbit known,” Scott Sheppard at the Carnegie Institution of Washington told the Guardian. “It extends the known boundary of the observable solar system.”